After closing higher on Friday, Singapore stocks fell once again, with Hutchison Port Holdings Trust leading the declines.
The city-state was down as much as 0.4%, widening what will be its worst month since October last year.
Investors are expecting quiet trading conditions, but will be monitoring news wires closely as geo-politics and trade concerns continue to remain relevant, said Nick Twidale, chief operating officer at Rakuten Securities Australia in a daily morning note.
Golden Agri-Resources Ltd and Singapore Press Holdings Ltd were among the biggest drags, falling 1.8% and 1.3%, respectively.
Philippine shares fell as much as 0.6%, with heavyweight PLDT Inc the biggest drag. The telecommunications firm was down as much as 3.9%, its biggest drop in about eight weeks.
Fio Dejesus, an equity research analyst at RCBC Securities, said foreign outflows could lead markets going forward, as investors factor in ensuing trade uncertainty and the end of the earnings season.
The Philippine peso was 0.1% weaker compared with broad appreciation across units in the region.
Elsewhere markets all edged higher, while Indonesian shares were up as much as 0.7% to a near two-week high. It remained on track for a third straight session of gains.
Financials in the country led the gains, with Bank Central Asia TBK PT and Bank Rakyat Indonesia (Persero) TBK PT up 0.8% and 2.1%, respectively.
Thai shares gained 0.1% in early trade as a pro-army party hopes to seal a deal on Monday end opposition hopes of keeping the military out of politics.
Energy and financial stocks raked in much of the gains with PTT PCL being among the biggest boosts, up 0.6%.
(Reporting by Nikhil Kurian Nainan, additional reporting by Rashmi Ashok; editing by Uttaresh.V)